Technology Editor

FAKE Woolworths, Coles and Harvey Norman gift vouchers are circulating on Facebook in what retailers warn is a scam designed to collect personal information.

The $400 or $500 vouchers have spread quickly because of what appears to be endorsement from Facebook friends. Complicating matters is the fact the retailers often have real gift voucher competitions running on their official pages.

"Please be aware there are some possible email, survey, website and Facebook scams currently circulating using the Woolworths name and logo," a Woolworths spokesman said on Tuesday.

The scams direct people to a website, for instance Woolworthsfree.net or harveynorman.org, offering free gift vouchers to those who follow three "simple steps".

The site has a counter that appears to show the vouchers rapidly running out in real time, "thank you" comments from what appear to be real Facebook users and a section claiming more than 6 million people have ''liked'' the page so far.

Software architect Troy Hunt, who uncovers online scams on his blog, wrote that the "sense of urgency", apparent popularity and air of authenticity attracts unsuspecting victims. He said he had analysed the code line by line and all of it was fake.

He said he believed the scammer was located in Albania and this meant it was difficult for authorities to tackle the scam.

"People in Australia being scammed by a guy in Albania using a server hosted in Germany. Who do the cops speak to?" Mr Hunt wrote.

"My experience talking with the authorities about the call-centre scammers shows that things like this just get filed away in the 'too-hard' basket."